The immune system of a monogastric animal is to a large extent located in the gut region. The immune system on the gut level is influenced in different ways by the feed that is ingested by the animal. Naturally, a good uptake of nutrients by the animal results in a better general health, a better growth and a better resistance against diseases for the animal. However, more and more evidence has become available on the fact that specific components in the animal's diet can have a more direct impact on the immune system at the gut level.
In monogastric animals, like pigs and chicken, the digestive system is simpler compared with ruminants, like cows and goats. The small intestine is the part of the gastrointestinal tract between the stomach and the large intestine, and is where much of the digestion and absorption of food takes place. The small intestine has three distinct regions—the duodenum, jejunum, and ileum. The primary function of the small intestine is the absorption of nutrients and minerals from food, but it is also an important part of the immune system on the gut level. The small intestine is covered by a mucosal tissue where a continuously regenerating mucus layer serves as protection against harmful microorganisms and toxins.
Intestinal villi are small, finger-like projections that protrude from the epithelial lining of the intestinal wall. They are covered predominantly with mature, absorptive enterocytes, along with occasional mucus-secreting goblet cells. Villi increase the internal surface area of the intestinal walls making available a greater surface area for absorption. An increased absorptive area is useful because digested nutrients (including monosaccharide and amino acids) pass into the semipermeable villi through diffusion, which is effective only at short distances. In other words, increased surface area (in contact with the fluid in the lumen) decreases the average distance travelled by nutrient molecules, so effectiveness of diffusion increases. The villi are connected to the blood vessels so the circulating blood then carries these nutrients away. Crypts are moat-like invaginations of the epithelium around the villi, and are lined largely with younger epithelial cells which are involved primarily in secretion. Toward the base of the crypts are stem cells, which continually divide and provide the source of all the epithelial, cells in the crypts and on the villi.
It is commonly known in the art that various short chain fatty acids as well as their respective glycerol monoesters seem to have different positive effects on animal health. For example, butyric acid helps to maintain and restore the integrity of the gut by stimulating cell proliferation and growth of the intestinal villi.
There are several benefits associated with distributing short chain fatty acids as glycerol esters. Glycerol esters are less corrosive than the corresponding free acids, facilitating handling and transportation of the products. Some of the short chain fatty acids, like for example butyric acid and valeric acid, have a very unpleasant smell. The corresponding glycerol esters of these acids are more or less odorless. Additionally, glycerol esters bind the short chain fatty acids, enabling them to reach further down in the gastrointestinal tract of a human or an animal before being adsorbed to the bloodstream.
It is known from SE1500157-1 that glycerol ester compositions comprising a high amount of glyceryl monovalerate inhibits the growth of gram positive bacteria, like for example Clostridium perfringens, and that such compositions prevent the prevalence of the disease necrotic enteritis in galloanserae.
It has now further been found that the renewal and growth of epithelial cells in the small intestine of a monogastric animal is significantly improved when the animal is fed a glycerol ester composition comprising glyceryl monovalerate. This in turn helps to maintain the lumen in a healthy, intact state, preventing pathogenic bacteria from adhering to the intestinal lumen and causing a bacterial inflammation. Glyceryl monovalerate has also been found to inhibit the growth of pathogenic bacteria as well as to reduce the invasiveness of these bacteria. This means that glyceryl monovalerate can be used in a multifunctional way to inhibit the adhesion of pathogenic bacteria to the intestinal lumen of monogastric animals, and thereby prevent bacterial inflammation in these animals.